G7 Summit 2015: Secrets of the world's most powerful people

You may know everything there is to know about the policies being discussed at the G7 Summit next week, but how well do you know the leaders who will be discussing them?

Not many people know that summit host Chancellor Angela Merkel’s childhood nickname was “Kasi” – short for her maiden name, Kasner.

The most powerful female politician in the world also wears $98 Boccia Titanium watch on her wrist. German jewellers refer to it as a “watch for people who want to know what time it is”.

She’s not the only leader in attendance who foregoes pretention: French President Francois Hollande often ditches his armoured limousine to putter through the streets of Paris on a moped.

Like President Hollande, Italian Prime Minister Matteo Renzi is also sometimes spotted in jeans and a leather jacket while riding his motorcycle.

More embarrassingly, he was once styled for a magazine cover shoot to look like Fonzi from the TV series, Happy Days.

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According to his biography, British Prime Minister David Cameron is the master of "chillaxing". He does so by lobbing a few shoots from his tennis ball machine, which he has nicknamed “the Clegger”.

He also likes to belt out a bit of Sinatra on his karaoke machine – favourite track: My Way.

Canadian Prime Minister Stephen Harper also has a yen for karaoke and he plays the piano, too.

U.S. President Barack Obama collects Spider-Man comics and was known in high school as the "O'Bomber" because of his skills on the basketball court.

Last but not least, Japanese Prime Minister Shinzo Abe has had the same favourite foods since childhood: Korean BBQ, Japanese noodles, ice cream and watermelon.

From Nazi sympathizer to G7 host: The Schloss Elmau story

They may lead seven of the most powerful nations on earth, but at the end of a long day in Schloss Elmau, they’re still as human as we are.